Clinical Improvement in Early-Onset Interstitial Lung Disease Using Rituximab in Children With Antimelanoma Differentiation-Associated Gene 5-Positive Juvenile Dermatomyositis

Objective. Children with juvenile dermatomyositis (JDM) and antibodies to antimelanoma differentiation -associated gene 5 (anti-MDA5) are at increased risk of severe disease complications, including interstitial lung disease (ILD). Data regarding treatment of disease complications in this patient population are limited. In this study, we examined the disease course of children with JDM and anti-MDA5 antibodies before and after treatment with rituximab (RTX). Methods. Patients aged 2-21 years and seen at the Children's Hospital at Montefiore between July 2012 and August 2021, with a diagnosis of JDM, positive anti-MDA5 antibodies, and evidence of ILD, and who were treated with RTX were eligible for inclusion. Retrospective clinical and laboratory data were reviewed. Results. Five of 8 patients with positive anti-MDA5 antibodies had evidence of ILD (62.5%). Four patients had data available for review. All patients received at least 5 courses of RTX infusions, with discontinuation of steroids by an average of 12 months after starting RTX and a decrease to fewer than 2 concurrent medications by the fifth course of RTX. Indicators of ILD on high -resolution computed tomography and pulmonary function tests either improved or fully resolved over the course of RTX treatment for all patients. Patients also demonstrated resolution of active cutaneous manifestations and musculoskeletal disease activity. Conclusion. To our knowledge, this is the first study to examine the use of RTX in children with JDM and anti-MDA5 antibodies, with notable improvements in ILD, cutaneous, and musculoskeletal manifestations. Further studies are needed to better understand the efficacy of RTX for JDM disease -related complications.